Johannesburg's fearful reputation precedes itself, and visitors arriving for the first time are bound to brace themselves for the worst.

Take a look at any guide-book, and, frankly, you'd think twice about coming here.

"Violent crime is rampant," says one, "lots of guns" another.

Africa has moved in where whites have left

I've lived, happily, in Lagos and Luanda, two African cities notorious for armed crime, but I still came to Johannesburg with a degree of apprehension.

On a continent of violent cities, Johannesburg, is, so they say, the worst of all.

Drive through the wealthy - predominantly white - northern suburbs, and you'll see high walls and electric fences, hiding houses which are in turn protected by alarm systems, metal grilles, and infra-red sensors.

This is the architecture of fear, and it is hard to feel relaxed in such an environment.